The invention relates to an assembly for opening and closing a liftgate of a motor vehicle. More specifically, the invention relates to an automated assembly designed to move a liftgate of a motor vehicle between an open position and a closed position.
Motor vehicles commonly include a liftgate typically connected to the rear of the vehicle. These liftgates are pivotal between an open position and a closed position to selectively provide access to the rear compartment of the vehicle. These liftgates are typically manually operated by pivoting the liftgate about a pair of hinges between the open and closed positions. A pair of hydraulic or pneumatic cylinders are often connected between the liftgate and the vehicle to assist in the opening of the liftgate and in maintaining the liftgate in the open position.
There is a desire to provide operators of motor vehicles with the ability to open and close liftgates free of manual assistance. This feature of providing power to a liftgate in a manner that moves the liftgate between its two extreme positions could be easily obtained if the task were merely to provide and remove access to a compartment within a motor vehicle. The task is, however, more extensive than that. The ability to open and close the compartment must be provided only when it is coupled with the ability to manually move the liftgate without having to provide an additional force to overcome the automation system. Further, the assembly that creates the force to automatically move the liftgate must be lightweight and minimally impact the capacity of the compartment to which the liftgate provides access.
Attempts have been made to provide a power liftgate drive mechanism that will automatically raise or lower the liftgate between its open and closed positions. U.S. Pat. No. 5,448,856, issued to Moore et al. on Sep. 12, 1995, discloses a powered liftgate mechanism. This mechanism includes a motor which moves a crank arm using an assembly that includes a worm shaft and gears. While the motor provides a force to move the liftgate between its open and closed positions, it requires the assistance of gas springs or struts to move the liftgate. Little mechanical advantage is provided by the powered liftgate mechanism. Therefore, when using the mechanism disclosed in this patent, modifications to the motor vehicle are required before the liftgate mechanism may operate correctly.
A power liftgate drive assembly moves a liftgate of a motor vehicle between an open position and a closed position. The power liftgate assembly includes a bracket that is mounted to the motor vehicle adjacent the liftgate. The drive mechanism is fixedly secured to the bracket. The drive mechanism provides a bidirectional rotational force. A gear is pivotally secured to the bracket. The gear is coupled to the drive mechanism to receive the bidirectional rotational force to pivot the gear with respect to the bracket. The gear defines a slot extending between first and second ends. The power liftgate drive assembly also includes a striker bar coupled to the gear. The striker bar slides through the slot. A guide rod connects the striker bar to the liftgate. The power liftgate drive assembly also includes a latch secured to the gear and operable between a latched position and an unlatched position. The latch engages the striker bar when in the latched position. This prevents the striker bar from moving along the slot. The striker bar moves through movement of the gear which is moved to power the liftgate between the open and closed positions. The latch disengages the striker bar when in the unlatched position allowing the striker bar to move along the slot allowing the liftgate to be moved manually between the open and closed positions.